When Paul Pierce defends Lebron James, good things happen for the Celtics. Or, to put that better, bad things happen less often.

Tom Haberstroh reached out to ESPN researcher Peter Newman and ESPN’s director of analytics (and noted statistical genius) Dean Oliver to break down how Boston defends Lebron James. Although Boston’s team defense means no one player is ever fully responsible for defending his man, Pierce defended James more impressively than any of his teammates.

According to Newmann and Oliver, Pierce checked LeBron 69 percent of the time, with Rajon Rondo, Jeff Green and Marquis Daniels (no longer with the team) filling in the rest. But against Pierce, LeBron shot just 43 percent from the field and his efficiency plummeted to depths rarely seen from him. In fact, LeBron scored 75 points per 100 possessions with Pierce covering him, down from his 93 points per 100 possessions when guarded by all other Celtics defenders.

That’s a huge difference, and considering how often the ball is in LeBron’s hands, it’s imperative for the Celtics that Pierce to avoid foul trouble.

The experts also noted that the “Rajon Rondo on Lebron James” strategy, which jump-started a Boston run during a midseason win, was unsustainable. In fact, it was worse than unsustainable. It was just bad. Kind of how you’d expect it to go when a 6’1 player with arms the width of a toothpick needs to defend a 6’8 player who could be a stunt double for a locomotive.

Keeping in mind that Pierce held LeBron to 75 points per 100 possessions, what would you guess LeBron’s efficiency against Rondo was this season? Answer: 135, or just about twice as lethal as when Pierce was his primary defender. Stats & Info found that LeBron shot 60 percent on his field goals against Rondo, which also includes some and-1 opportunities when Rondo couldn’t match LeBron’s strength inside.

If you’re like I am and just remembered, “Man, the Celtics could have had Tony Allen for pretty cheap,” Allen only played against Lebron for 21 minutes this season, all of which were played during a March game in Miami. During those 21 minutes, Lebron shot a nifty 100% from the field. But he only shot the ball seven times, which could be an indicator of three things:

1) Allen defended James quite well despite all the makes; James had trouble finding shots

2) James didn’t care very much about scoring, mostly because his team was on its way to a 118-85 victory, and also, seven shots is a whole lot to make in only 21 minutes without missing a single time

OR

3) Allen didn’t even defend Lebron, because Shane Battier took care of that while Allen guarded Wade. Quite frankly, I don’t know if that’s true. I don’t know who defended who. I know Lebron shot 7-7 while Tony Allen was on the floor, but I don’t know whether Allen was defending James. So basically, the “7-7 shooting while Tony Allen was on the floor” stat is useless.

Oh, well. I suppose it’s a waste of time to think about Tony Allen’s defense on Lebron anyway. The Celtics have Paul Pierce, who figures to play the lion’s share of the minutes, and he does a damn good job defending the so-called King.